Steam generator



C 9 l Aug 2 l 27 T. cLARKsoN S TEAM GENERATOR Filed sept. 7. 192s i 40by increasing tlie number of thimbles in ling throughout the main partof the gener.

Patented Aug. l927. Y f I y i i uN-irEDsTATEs PATENT OFFICE.

THOMAS CLARKSON, OF-LONPON, ENGLAND.

STEAM GENERATOR.

Application led September 7, 1926, Serial No. 134,083, and in GreatBritain September- 17, 1925. This invention relates to water heaters orspending dimension of this annular space 55J steam generators of "thekind in whicli'hot at or towards the inflow end. gases flow `over andbetween a series Three alternative constructions of heater ofclosed-ended water-containing. thimbles or generator for carrying theinvention into which radiate inwards from an annular effect areillustrated somewhat diagrammatisteam and water chamber into a heatinglcally by way of example in the accompany- 00 space provided with acentral -plugor baiile. lng drawings, in which The invention isparticularly applicable Figure l is a sectional side elevation of a toheaters of the above kind employing waste heater having a greater numberof water` or exhaustvgases, for example, from an in- 'tubes in the upperZone than in the lower ternal combustion engine although it may 'zone,65 also be employed in connection with generi Figure 2 `is a section onthe line 2--2 of i ators heated by the combustion of fuel Flgure l, andA i directly beneath them. Flgure 3 is a section on the line 34-3 of 35In water heaters of the above kind the Figure 1.

rate of flow of the hotgases through the .Flgllles 2 and 3 are SeCtionssimilar to 70 annular space. into which the thimbles radi- Flgures 2 and3 showing in an exaggerated ate tends to decrease as these gases give up.form the m-anner in which the variation in their heat to the water,owing to the dimithe number of tubesl causes a, reduction in nu'tion inthe volume Of the gases, and the' the cross-sectional area of the gaspassage,

objectoi1 the present invention is to obviate and Figure 4 is asectional elevation of an 75 this loss in the mt@ lof flow of thesegases alternative form of generator in which the v and thus to maintaineilicient transference Walls 0f the gas passage are tapered for the ofheat, which largely depends upon the vepurpose of reducing itscross-sectional area locity of gases in relation to the heat abat theoutlet end.

e SOI-bing- Surfag, Y In the onstruction illustrated the gener- 80v Tothis end the heater is so constructed atOI' COIIlpI'lSeS an annularsteam and water that tlie average cross-sectional area of the Space Abounded by cylindrical walls B, C, annular space through which the hotgases 118.1111161 one C of which carries projecting tlow over andbetween the thimbles is less radlally inwards therefrom a seriesofthilntowards the outflow than towards the inbles D. These thimbles arepreferably 35' flow end of this space, so that the velocity tapered as'shown with their smaller ends of these gases, when cooled by and afterdirected inwardly, but their axes lie conpassing over the thimbles,remains substanvenlently'truly radially with respect to thetiallyconstant throughout i its passage axis of thel generator. The thimbles Dare through the heater. The average cross-secdiSPOSGdAiIl 3111111131'I'OWS, each row lying in 90 tional area of the annular space may difaplane normal to the axis of the generator Vfer at successive points inthe length of the while the length of the thimbles is such as.

generator and t is result may be secured to leave a central cylindricalspace extend- Ysuccessive rows or groups of rows from ator. Within thiscentral space is disposed am the 'inlet towards the outlet end of the acylindrical core or plug E which may bev hot gases, the size of thesethimbles beeither formed of refractory material or 'of ing constantthroughout. Alternatively, the steel or other tubing as shown.Alternasize of the thimbles in the rows or groups tively the` core maybe formed partly .0f

of rows may be increased towards the end metal tubing and partly ofrefractory ma- 10o `through which the hot gases escape, the acterial. YThe core E is conveniently sustual number of thimbles in each row beingpended from'the upper or out'low end of the v constant throughout. Yetagain, theV inner generator as shown by means of a rod F enor outerwalls which enclose `the annular gaging at one 'end a suitablyscrewthreaded space into which the thimbles project 'may bore in acap'meinber E1 for the plug E and 105. he tapered, so that the radialdimension of at the other end connected to thecentre of this gas spacewlll be less at ortowards the a bridge piece'l F1 extendingdiametrically gas outflow end of the heater than the correacross the gasoutlet passage C1 of the gen-v erator. As will be seen, this structureprovides an annular space between the central core or plug E and theinnerwall C" of the 4steam andwater space A. Hot gases enter thisannular space through the inlet opening C? and after flowing over andbetweenthe thimbles D, escape through the outlet passage C1. Thethimbles are formed oli uniform dimensions but the number of thimbles ineach of the annular rows which lie in transverse sections taken throughthe generator is increased, preferably. by stages, from the iniow endtowards the outflow end. Thus, for example, in the constructionillustrated while a certain number, say 1 0, of the annular rows ofthimbles adjacent to the inflow end each contain asimilar number ofthimbles, for example 34, as shown in Figure' 2, a certain number, say13, of the annular rows of thimbles adjacent to the outow end ,C1 areeach provided with a larger number of thimbles, for example 37, as shownin Figure 3. The remaining number of annular rows of thimbles which liebetween the top and bottom stages, compris ing say 14 rows, may havesome intermediate number of thimbles, for example 36 thimbles per row.

The arrangement described above is suit- .able for a generator havingapproximately an external diameter of 5 feet and a total overalllengthof about 15 feet.

As will be seen fromA the drawings, the

thimbles in adjacent rows are staggered' .while their inner closed endslie near to the outer wall of the central core or plug E. It

' will be understood that instead of the gases flowing in the upwarddirection, as in the particular exam le illustrated, they mayv flowdownward t rou h the heater, in which case the number of t imbles in theuppermost row or group. of rows will be less than those in theintermediate and lowest group of rows.

Within the steam and water space A is disposed a cylindrical baie memberG which is carried by the outer wall B of the generator on short studsG1 and extends conveniently Jfrom adjacent to the lower end of th steamand' water space to a short distance above the last of the annular rowsof thimbles. This cylindrical baile plate G -serves to assist the Watercirculation, an up- Ward current tending to take place within -thebalile plate and a downward current flowing outside it. The feed wateris introduced through the outer wall of 'the generator at some ointWhere this water will strike against t e balileplate G, for example afew inches below the top edge of the baffle -as indicated at H.

Figures 2 and 3 are cross-sections similar to Figures'2 and 3 of agenerator in which the number of tubes towards the out- "let end of thegenerator is considerably' greater than they number of similartubestowards. the inlet end of the generator, Such a construction would-notbe used in practice but is given for the sake of clearness to show in anexaggerated manner how the reduction in the cross-sectional -area of thegas passage is produced. Figure 4 shows an alternative construction ofgenerator according to this invention in which the inner wallJ of thewater and steam space .K which carries the thimble tubes L is tapered,while the central plug or baille M is also tapered so that'itliesadjacent'to the inner ends of the tubes L at all points in itslength. In this construction the number of thimble tubes in eachcircumferential row would normally be the same, and it will be seenthat; the cross-sectional area of the gas passage will be less at theoutlet end of the heating space than at the inlet'end.

The improved generator according to this invention may be supplied withhot gases in-various ways.' FV generator is employed for utilization ofwaste heat it may be in some cases conveniently arranged for the hotgases to enter at the lower end whence theyY pass upwards through theannular gas space over' the thimbles into the outlet passage in theupper end ofthe generator. A chambei may be provided at the lower end ofthe generator into which 'the hot gases enter, this chamber beingarranged with a helical passage into which the gases are led so thatvthey will tend to flow spirally 'up through the gas space around thecentral core. This chamo1" example where the` ber may be provided with asecond open- I space, while, when raised, the tube will tend to close toa greater or less .extent'the upper end of the annular gas space andwill cause the gases to How then wholly or partially through the centraltube.

It is to'be understood that the constructional details of the apparatusmay be varied within wide limits without departing from the invention.

What I claim as my to secure by Letters invention and desire atent 1s: Y

1. A lwater heater of the class described',- .comprising in combinatlonan annular water chamber surounding a heating-space through which hotgases can flow, closed-ended water-containing thimbles extendingradial-V ly into the heating space from the water ended water-containingradially into the i around the thimbles space, ing space lnear the otherend Lacasse chamber, an inlet for the hot gases at one end of thechamber, an outlet therefor near the other end and a baille of circularcross'- section' disposed centrally within the heating thecross-sectional area of the heatbetween and around the thimbles be'smaller towards the outlet than to# war 'the inlet for the. heatinggases for the purpose specified.

2. A water heater' of the class described comprising in combination anannular water chamber surrounding a heating space through which hotgases can flow, closedthimbles extending heating space .from the aninlet for the hot gases at chamber, an outlet therefor and a baille ofcircular cross-sectionfdisposed centrally within the water chamber, oneend of the 'heating space, the average cross-sectional area of theheatinge space between and ing reduced in stages om the inlet for theheating gases towards the outlet so that the rate at which' these hotgases iiow over stantially constant.

a 3. A water heater of the class described comprising ber surrounding avheating space through which hot gases can flow, water-containingthimbles extending radialf lyl into the heating space v:from the water eamber in a plurality of superimposed. rows, an inlet for the hot gasesat one end of the chamber, an outlet therefor at the opposite endthereof and a baille of circular the thimbles is subcross-sectiondisposed centrally within the heating space, the number 'of thimbls'ineach row towards the gas outlet end being v rows,

in combinationan annular cham- I closed-ended successively increasedfrom thek gas inil eater than the number of similar thimbles 1n the rowstowards the gas inlet end for the purpose specifi d e l 4. A waterheater of the class described comprising in combination an annular waterchamber surrounding a heating space through which hot gases can flow, apluralit of closed-ended water-containing thim les of similar dimensionsextending radially into lthe heating ,"spa'ce `from the water chamber ina series of superimposed an inlet for the heating gases at one end ofthe chamber, an outlet therefor at the other end and a bailie ofcircularv crosssection disposed centrally within the heating space, thenumber of thimbles in each stage of rows being successively increased`froin the as inflow end towardsv the outiiow end as and for the purposespecified.

5. A water heater of the class described .comprising in combination anannular water chamber surrounding a heating space through which hotgases can flow, a plurality lof closed-ended water-containing thimblesof similar dimensions extending radially into the heating space from thewater chamber in a. series of rows arranged in staggeredrelationshipwith one another, an inlet for'the heating gases at one end of thechamber, an outlet therefor at the other end and a baille of circularcross-section disposed 'm centrally within the heating space, the numberof thimbles in each stage of rows being ow end towards the outiow endasv and for the purpose specified.l

In testimony whereof I have signed my name to thisspecication.

THOMAS CLARKSON.

